The proposed two-and-one-half day conference will be held at the Environmental and Occupational Health Sciences Institute (EOHSI) located at Rutgers/University of Medicine and Dentistry of New Jersey (UMDNJ)-Robert Wood Johnson Medical School on June 21-23, 2000. The conference participants will discuss known and potential relationships between environmental exposures and various endemic/epidemic health concerns characterized by medically unexplained physical symptoms. The conference format includes one-and-a-half days of lectures and didactic presentations aimed at providing an initial consensus on nomenclature and introducing classification of syndromes. Two separate half-days are devoted to the discussion, identification and reporting of three potentially major areas of research in the field. Discussion groups will be charged with the task of addressing three major topics: 1) the nature and mechanism(s) of relationships between environmental exposures and symptoms without apparent disease, 2) determination of optimal nosological classification of symptom complexes, and 3) experiments/epidemiological studies that would aid in the interpretation of environmental and psychosocial contributions to these physical disease complexes. Eleven domestic and three international contributors are drawn from academia, State and Federal government. Contributors will present aspects of current thinking on epidemiologic observation, classification, psycho-social and biological mechanisms. Based on previous experience with the organization of conferences of this type at EOHSI, approximately 100 local and national attendees are anticipated. The organizers anticipate submission of the proceedings of the meeting for publication in Environmental Health Sciences. The overall goal of the conference is to provide a point of departure for the harmonization and classification of environmental/physical syndromes that currently defy medical diagnosis. Furthermore, following discussion of the issues in the field the organizers hope to identify gaps in research and possible avenues of investigation.